Engagement between a roller end and a bearing race flange is commonly seen in tapered roller bearings and in cylindrical roller bearings. The contact serves to guide the rollers and bear axial load. The conditions of the contact are determined by a flange and roller end geometry, which in turn, dictates the axial load carrying capacity of the bearing as well as a flange torque and a wear rate at the surfaces of the roller end and the flange.
For tapered roller bearings, the contact portion of the roller ends is often machined spherical in shape. Spherical roller ends are also used in cylindrical roller bearings (as disclosed within U.S. Pat. No. 6,530,693). This results in a contact ellipse between the inner raceway flange and roller end whose major axis is arranged in the radial direction of the bearing. As the contact load increases, the contact ellipse may be truncated by an undercut or an outer diameter of the bearing flanges. To reduce the risk of truncation of the contact footprint between the roller end and the flanges, and thus reduction of edge loading, cylindrical roller ends are often machined to a torus (as disclosed within U.S. Patent Application Publication No. 2003/0091255) to produce an ellipse whose major axis lies along a circumferential direction.